Editor's note: Julian E. Zelizer is a professor of history and public affairs at Princeton University's Woodrow Wilson School. His new book, "Arsenal of Democracy: The Politics of National Security -- From World War II to the War on Terrorism," will be published this fall by Basic Books. Zelizer writes widely on current events.

PRINCETON, New Jersey (CNN) -- President Obama currently has the polls on his side. In numerous surveys, Americans have said they are pleased with Obama's performance thus far and confident the president can fix the economy, acknowledging this will take some time.

The political question for the White House is how long those poll numbers will last. At some point, the "Bush Economy" is going to become the "Obama Economy."

When that happens, Obama will be in serious political trouble unless the economy has turned around. Republicans will be able to argue that the administration's plans are not working and this perception will greatly diminish public support for the White House.

Thus far, Obama has been able to avoid this charge. He has been able to continue pointing to the effect of decisions by the previous administration, as well as public policy and economic practices dating back to the 1980s, as the root causes behind our crisis. But this strategy will only last for so long.

For better or worse, most Americans have short memories when it comes to politics, and they evaluate their government based on what they see happening to their own economic circumstances.

Commentators have frequently compared Obama to Franklin D. Roosevelt by remembering another president who took power during hard economic times and was able to retain enormous political capital even as conditions were poor.

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But the presidencies of Gerald Ford, Jimmy Carter and Ronald Reagan offer a very different kind of model. During the 1970s and early 1980s, the nation suffered from stagflation, the combination of high inflation and economic stagnation.

Prices rose, unemployment increased and a series of oil embargos left drivers sitting in long lines just to get half a tank of gas.

Each of the three presidents after Richard Nixon's resignation in August 1974 was burdened with the political effects of a stagnant economy. Gerald Ford took a number of steps to improve conditions.

As a fiscal conservative, Ford tried to reduce government spending. In 1975, he obtained support in Congress for a tax cut, and Congress also passed his energy plan, which established a long-term process of removing controls on the industry.

But in the end, none of this worked. To be sure, Ford had many problems beyond the economy. His pardon of Richard Nixon in September 1974 undermined popular goodwill that he really needed to move the nation beyond Watergate.

The president's struggles with foreign policy toward the Soviet Union elicited the anger of the right-wing of his party, who warned that détente posed a danger to the nation. But Ford's inability to stop stagflation was devastating.

By the fall of 1976, Jimmy Carter and his running mate, Walter Mondale, could pin the dire economy on the Ford administration, and there was little the president could do to repel these attacks.

"If you look at the things that best tell you the direction of the economy," Mondale told an audience of Polish-Americans in Milwaukee in September 1976, "every one says the economy is going down."

President Carter suffered the same fate. The same economic conditions that helped to bring him into office turned into an albatross on his presidency. Initially many Democrats, and even some independents and moderate Republicans, had been excited about Carter's outsider campaign and his determination to move forward on issues such as energy independence.

During his first 100 days, Carter's approval ratings were strong. But over the course of his presidency, stagflation made Carter appear to be an ineffective president. In 1979, Carter gave a televised speech to address the crisis that Americans were facing.

He said that "One of the visitors to Camp David last week put it this way: "We've got to stop crying and start sweating, stop talking and start walking, stop cursing and start praying. The strength we need will not come from the White House, but from every house in America."

Although the speech was well-received at first, it ultimately did not sit well with Americans who were hit that same year with another severe oil shock as a result of an OPEC oil embargo, To many voters, his words turned into another example of how Carter had failed to take command of economic conditions.

As a result, many Americans started to find the arguments from conservatives more attractive, as the right promised that tax cuts and deregulation were essential to ending the misery. As Reagan said in one of his most famous lines, "A recession is when your neighbor loses his job; a depression is when you lose yours. And recovery is when Jimmy Carter loses his."

Though Reagan entered office with significant political momentum, driven by an energetic conservative movement, his first year was not so smooth. While Reagan was able to pass a historic tax cut through Congress in 1981, the recession that hit the already ailing economy in 1982 as a result of the Federal Reserve's anti-inflationary monetary policies produced talk of a "Reagan Recession." iReport.com: How is Obama handling the economy so far?

Democrats developed the "fairness issue" in the 1982 midterm campaign as they stressed the economic struggles of so many voters. Reagan's attempt to explain that the recession resulted from the "failed policies of the past" did not work.

While Republicans retained control of the Senate in 1982, Democrats enjoyed sizable gains in the House of Representatives. Under Speaker Tip O'Neill, House Democrats would undermine many of Reagan's domestic and foreign policy initiatives.

The difference between Reagan and his two predecessors was that economic conditions finally started to improve the following year. This allowed the president to run a campaign in 1984 that stressed it was "Morning Again in America."

The clock is ticking for Obama. There will likely be a tipping point when the approval ratings start to slide and a majority of Americans start to associate the recession with this White House.

Arguments about how the crisis started earlier will sound more like a defeated leader, trying to explain his failures, than a reasoned leader trying to explain the situation we face. That's how politics works.

It will be politically essential that Obama's early policies, particularly the economic stimulus bill and financial bailout, stop the downward slide of the economy and create some kind of stability. Otherwise, the president will find himself in rough waters.

The opinions expressed in this commentary are solely those of Julian Zelizer.